Recent three-month history left a negative Pacific warm-cold volume slope contrast in 1980-2024 fits

We tested whether recent surface temperature and subsurface volume changes explain a published warm-cold slope contrast for six-month Pacific warm water volume change. We used frozen NOAA GODAS and ERSSTv5 data and 531 monthly starts from April 1980 to June 2024. The fit controlled for starting volume, month and time. Adding prior three-month changes in temperature and volume gave a warm-minus-cold slope of -1.17 in units of 10^14 cubic metres per degree C. Its conditional 95% three-year block interval was -1.80 to -0.54. The matched base contrast was -1.23. The paired change was 0.05, with limits of -0.09 to 0.21. These simple history controls did not clearly explain the contrast. This is a conditional association, not a causal discharge effect or a forecast test. One reanalysis, few climate cycles, a fixed temperature reference and limited history terms constrain the result. Code, exact input hashes, aggregate estimates, coefficient draws, an independent numerical audit and a figure are included. External source records and monthly derivative records are excluded.

ENSO · warm water volume · recharge · history adjustment · conditional association